alderman
Addicted to ArboristSite
The only thing I know is that the specs of the 488 and 757 were found to be very optimistic, when those were subjected to independant lab testing (dyno etc).
The test was flawed in several ways, but there is no reason to doubt the lab results.
Sorry, I have no link to that test report, just a paper printout - but it is somewhere in the archives........
If the test is flawed than I would think there would be every reason to doubt the lab results. I can't argue whether the specs are optimistic or not, but I can argue that results from flawed tests should be taken with a grain of salt.